Foam producing nozzle

ABSTRACT

A foam producing nozzle of the type using an air and fluid mixing chamber for discharging a foaming stream from the nozzle. A pair of spaced orifice plates are between the nozzle inlet and the mixing chamber and arranged to enhance the foam producing effect.

0 United States Patent 1191 1111 3,784,11 1 Piggott Jan. 8, 1974 [54]FOAM PRODUCING NOZZLE 2,630,183 3/1953 Foutz 239/427 X 61,412 1 1968 C l239 432 X [75] Inventor Richard Bellwood m 3,561,536 2i1971 H n shaw 169/15 x [73] Assignee: Spraying Systems Co., Wheaton, Ill. FOREIGNPATENTS OR APPLICATIONS [22] Filed: I Mar. 29, 1972 568,669 1 1959Canada 239 432 [21] Appl. No.: 239,167

Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-John J. Love[52] U.S. Cl 239/427.3, 239/432, 239/590.3 51 1111. C1 B05b 7/00 [58]Field of Search 239/343, 370, 427,

239/428.5, 432, 590.3, 590.5, 597, 171, [57] ABSTRACT 4273; 169/15 14 Afoam producing nozzle of the type using an air and 5 6] References Citedfluid mixing chamber for discharging a foaming stream from the nozzle. Apa1r of spaced orifice plates are be- UNITED STATES PATENTS tween thenozzle inlet and the mixing chamber and ar- 2,774,583 12/1956 Haftke169/15 X ranged to enhance the foam producing effect, 3,202,360 8/1965OBrien 239/596 X 1,063,913 6/1913 Cornelius 239/599 X 5 Claims, 6Drawing Figures PATENTED JAN 74 SflEET 1 OF 2 PATENTED JAN 81974 SHEET 2BF 2 1 FOAM PRODUCING NOZZLE The present invention is directed to newand useful improvements in nozzles of the type used to mix air with afluid stream for the purpose of emitting a foaming stream from thenozzle.

Foaming streams are produced by a mixture of a chemical, water and air.Foam type streams are sometimes used for the purpose of rendering asprayed area visible due to the easily identified particles of foam.Foam type-sprays are also used in aircraft spraying to reduce winddispersion of the spray. A foaming action causes coagulation of smallparticles into larger liquid particles which are more easily identifiedthan small particles and which are less susceptible to drifting due towind effects.

In producing a foam type spray the extent of the particle size andefficiency of the foam produced for the above mentioned purposes isdependent upon the thorough mixing of air with the liquid. 'With this inmind, the major purposes of the present invention are to arrange airentraining, foaming nozzles in such a way as to provide a more efficientmixing of air and liquid with a resultant increased foaming effect toprovide a larger particle size and a more easily identified foam, and atthe same time arrange such nozzles in such a way that they areeconomical to manufacture and easy to use with existing sprayingequipment.

These and other purposes will appear from time to time in the course ofthe ensuing specification and claims when taken with the accompanyingdrawings, in which:

FIG. 1 is a diagrammatic view illustrating a typical aircraft sprayingoperation;

FIG. 2 is a side view of a nozzle assembly incorporating the presentinvention and intended for use with an existing spraying assembly;

FIG. 3 is a sectional view of the nozzle body utilized in the nozzleassembly of FIG. 2;

FIG. 4 is a side view of another nozzle assembly incorporating theprinciples of the present invention;

FIG. 5 is a sectional view of the nozzle body illustrated in FIG. 4; and

FIG. 6 is a diagrammatic illustration of a boom spraying installationwhich is particularly suitable with nozzle assemblies of the typeillustrated in FIGS. 4 and 5.-

Like elements are designated by like characters throughout thespecification and drawings.

With specific reference to the drawings, and in particular to FIG. 1,the numeral 10 generally designates an aircraft carrying plural nozzles11 intended to emit fluid, insecticides, herbicides or other chemicalsover a predetermined swath width shown by the dimension S in FIG. 1. Inaircraft spraying of this type utilizing nonfoaming sprays, wind driftmay carry the sprayed particles considerably outside of the swath widthwith the result that the spray may be deposited on undesired areas.Also, wind drift may make it difficult to control the spray to provide arelatively uniform dispersal of sprayed particles. It is known that useof a foaming agent and a foaming spray will reduce the wind drifteffect, due to increase in particle size, and thus increase theefficiency of the spraying operation.

FIGS. 2 and 3 illustrate one embodiment of the invention utilizing aspray tip body 12 in a nozzle assembly which includes an inlet body 13having a strainer therein and an inlet fitting 14. A cap 15 isscrewthreaded on the inlet body so as to couple the nozzle tip body 12thereto.

A nozzle inlet body 13 and cap 15 as illustrated may be found inexisting spraying installations for use with other types of nozzle tipbodies.

The nozzle tip body 12 as illustrated in FIGS. 2 and 3 is intended andarranged for use when emitting a substantially solid stream which issuitable for use with aircraft spraying as described with respect toFIG. 1.

In accordance with the present invention, the nozzle tip body 12 isformed with an enlargement 16 at the inlet thereof for coupling to thecap 15 in FIG. 2. The nozzle tip body 12 is formed with an enlarged boreleading from the inlet end to a mixing chamber 17 in an intermediatelocation in the body. Apertures 18 are formed in the wall portion of thenozzle tip body which surrounds chamber 17 to allow air to be inducedinto the chamber 17 under the action of liquid flowing therethrough.

The nozzle tip body includes a tapered portion 19 of gradually reducingdiameter from chamber 17 to an intermediate portion 20 having a diametersmaller than an outlet bore 21. Outlet bore 21 extends from portion 20to the discharge end 22 of the nozzle tip body. The outlet bore 21 andportion 20 have a substantially smaller diameter than that of mixingchamber 17. The tapered portion 19, intermediate portion 20 and bore 21define a discharge passage from the mixing chamber. The reducedintermediate portion 20 defines a nozzle orifice for a generally solidstream emitted through the discharge end 22 of the nozzle tip body.

The inlet end of the nozzle body is provided with a bore 23 of slightlylarger diameter than the bore which defines mixing chamber 17 and theouter end of this bore is threaded as at 24.

A pair of nozzle orifice plates 25 and 26 are positioned within bore 23in spaced relation. The front surface 27 of one plate 25 defines therear side of mixing chamber 17. Orifice plate 25 is preferably formed asthe inner wall of a cup-shaped element 25a seated in bore 23, whileorifice plate 26 is preferably formed to bear against the outer rim ofthe cup-shaped element while having a projection 28 of reduced diameterwhich seats within the rim. A lock nut 29 is engaged with the threadedportion 24 to hold the plates 25 and 26 in the assembled relation shown.

In accordance with the present invention, the orifice 30 in the plate 25next to the mixing chamber has a smaller cross-sectional flow area thanthe orifice 31 in the second plate 26 closet to the inlet end. Byarranging the flow area as described and by arranging two orifice platesin a spaced relation in the inlet passage, an expansion chamber isdefined between the plates 25 and 26 which produces turbulance and athorough mixing of the liquid passing through orifice 30 and the airadmitted through the apertures 18 to mixing chamber 17. The thoroughmixing thus provided increases the foaming effect on the foaming agentcarried by the liquid being sprayed.

The solid stream passing through orifice 30 flares out to entrain theair entering through the apertures 18. This in turn produces a floodeffect through the tapered portion 19 and at the orifice definingportion 20. As the stream passes from the orifice defining intermediateportion 20 it is allowed to expand in the enlarged bore 21 whichproduces an additional mixing action to further improve foam quality.The length of the bore 21 should be at least three and one-half timesits diameter to prevent flaring of the spray as it leaves the nozzle tipbody.

Generally speaking, an increase in flow velocity through the mixingchamber increases the foaming effect and particle size. As contrastedwith this, the orifice plates actually reduce flow velocity below thatvelocity obtained with a single orifice plate However, with the twoorifice plates, the mixing effect actually increases and particle sizeis increased above that obtainable with a single orifice plate eventhough velocity is reduced.

Orifice 30 can be shaped to provide a sharp edge orifice which furtherimproves foaming effect. A radius type orifice as shown may also beused.

The diameter of the chamber defined between the plates 25 and 26 shouldbe at least one and one-fourth times the diameter of the orifice 30 toproduce proper turbulance and mixing with the air.

FIG. 4 illustrates another embodiment of the invention in which theprinciples of the invention are utilized with a nozzle tip bodyproducing a flat or fan-shaped foaming spray. The nozzle tip body 40 inFIG. 4 is coupled to an inlet fitting 41 through use of a cap of thetype illustrated in FIG. 1. The nozzle tip body 40, as will be apparentin FIG. 5, includes an enlargement 42 at the inlet end thereof to allowcoupling of the nozzle tip body to the inlet fitting 41 by the cap 14.In FIG. 5 the nozzle body is bored to define an intermediate mixingchamber 43 and a discharge passage 44 of smaller diameter than themixing chamber 43. Apertures 45 are formed in the nozzle body to allowair to enter the mixing chamber 43 under the influence of fluid passedtherethrough. In FIG. 5 a pair of spaced orifice plates are used as inFIG. 3. A first plate 46 is defined as the transverse wall of acup-shaped element 46a, while the second plate 47 is positioned acrossthe rim of this cupshaped element and includes a projecting portion ofreduced diameter 48 fitting snugly within the rim of the cup-shapedelement. The cup-shaped element 46a is seated in the nozzle tip body ina bore 49 of slightly larger diameter than that of the mixing chamber43. The outer end portion of this bore is threaded as at 50 to receive alock nut 51 which holds the orifice plates 46 and 47 in the assembledrelation illustrated.

In FIG. 5, a screen 52 is positioned across the opening between themixing chamber 43 and outlet passage 44. A ring 53 may be utilized tohold the screen against the shoulder between the mixing chamber 43 andoutlet passage 44. The outlet end of the discharge passage 44 has acurvilinear form and the end of the nozzle tip body is slotted as at 54to produce a fan-shaped or flat spray in a manner known to the art.

As in FIG. 3, the two orifice plates 46 and 47 have orifices sized sothat the flow area through the orifice 55 in plate 46 is less than theflow area through the orifice 56 in plate 47. Again, an expansionchamber is defined between the two plates 46 and 47.

In the embodiment of FIG. 5, the use of the two orifice plates producesa turbulent effect on liquid passing through orifice 55 and into themixing chamber for a thorough mixing of the air and liquid in the mixingchamber 43. The use of the screen enhances the formation of foam passingto the outlet passage 44.

In FIG. 5 the stream flares out as it passes orifice 55. Additionalflaring occurs at the screen 52. A flooding condition occurs in theoutlet passage 44.

As in FIG. 3, the orifice plates increase th foaming and mixing effect,even though flow velocity is reduced.

The ratio of the diameter of the expansion chamber between the orificeplates in both FIGS. 3 and 5 should be at least in the amount statedbecause with a lesser ratio and a lesser degree of expansion of thestream passing through the orifice in the outer plate, the pressureconditions tend to reduce the turbulent effect in the mixing chamber.

FIG. 6 illustrates a typical spray application utilizing foaming nozzletips of the type described with respect to FIGS. 4 and 5. In FIG. 6, forexample, a spray boom 57 carries a plurality of nozzle assemblies of thetype illustrated in FIG. 4 and designated at 58. In FIG. 6, the nozzlesare arranged for the purpose of providing plural fan-shaped spray areasF positioned next to one another.

In both embodiments the spacing dimension between the orifice platesshould be in the range of around onehalf to two times the internaldiameter of the cupshaped element to obtain proper action in theexpansion chamber. in the embodiments illustrated, the spacing dimensionis around seven-tenths the diameter. Spacings less than this tend toproduce too much flow straight from one orifice through another whilegreater spacings minimize the double orifice effect to an extentsubstantially like the effect obtained with a single orifice plate.

Use of the cup-shaped element for one orifice member in the arrangementrecited allows a simple changeover from one set of selected sizes oforifices to another, through endwise removal and replacement through theinlet bore.

Foaming nozzles of the type herein illustrated and described may be usedin installations other than aircraft spraying and boom sprayinstallations. They may, for example, be used with spray guns or otherspraying equipment wherein a foaming effect is desired.

I claim:

1. In a foam producing nozzle of the type defined by a nozzle bodyhaving an air and liquid mixing chamber defined in the body between aninlet end and an outlet end, and having air inlet apertures in the bodyleading to said chamber to induce the flow of air to said chamber underinfluence of a fluid stream passingthrough said chamber, the improvementcomprising a pair of spaced orifice plates positioned in a passage insaid body leading to said chamber, each of said orifice plates havingorifices axially aligned with said chamber and the outlet from saidchamber, one of said plates defining a side of said chamber opposite tothe outlet side thereof and the other of said plates being positioned inspaced relation to said one plate and between said one plate and theinlet side of said body, said plates defining therebetween an expansionchamber having a diameter substantially greater than the diameter ofsaid orifices, the orifice in said one plate being smaller than theorifice in said other plate, said chamber defined between said platesbeing closed to the exterior except for the orifices in said plates.

2. A nozzle as set forth in claim 1 wherein said first plate is definedas a wall of a cup-shaped element positioned within said nozzle body andsaid second plate is seated against the end of said cup-shaped bodyremote from said one plate, said cup-shaped element and second platebeing held within a bore of said body and 5. The structure of claim 3wherein said nozzle body is shaped to provide a discharge passage ofsmaller diameter than said mixing chamber, said discharge passageincluding an intermediate portion of a reduced diameter to define anorifice, said nozzle body including a tapered passage having a graduallyreducing diameter from said mixing chamber to said orifice diameter,said discharge passage having a substantially uniform diameter from saidintermediate portion to the outlet end thereof to provide a relativelysolid discharge stream. =1 i

1. In a foam producing nozzle of the type defined by a nozzle bodyhaving an air and liquid mixing chamber defined in the body between aninlet end and an outlet end, and having air inlet apertures in the bodyleading to said chamber to induce the flow of air to said chamber underinfluence of a fluid stream passing through said chamber, theimprovement comprising a pair of spaced orifice plates positioned in apassage in said body leading to said chamber, each of said orificeplates having orifices axially aligned with said chamber and the outletfrom said chamber, one of said plates defining a side of said chamberopposite to the outlet side thereof and the other of said plates beingpositioned in spaced relation to said one plate and between said oneplate and the inlet side of said body, said plates defining therebetweenan expansion chamber having a diameter substantially greater than thediameter of said orifices, the orifice in said one plate being smallerthan the orifice in said other plate, said chamber defined between saidplates being closed to the exterior except for the orifices in saidplates.
 2. A nozzle as set forth in claim 1 wherein said first plate isdefined as a wall of a cup-shaped element positioned within said nozzlebody and said second plate is seated against the end of said cup-shapedbody remote from said one plate, said cup-shaped element and secondplate being held within a bore of said body and against a shouldertherein by a retainer in screw threaded relation to said body andbearing against said second plate.
 3. The structure of claim 2 whereinsaid second plate includes a portion of reduced diameter fitting snuglywithin said cup-shaped element.
 4. The structure of claim 3 wherein saidchamber includes a screen remote from said first plate and on the sideof said chamber opening to said discharge passage, said nozzle bodybeing shaped, between said screen and the discharge end thereof, toprovide a flat, fan-shaped spray from the nozzle.
 5. The structure ofclaim 3 wherein said nozzle body is shaped to provide a dischargepassage of smaller diameter than said mixing chamber, said dischargepassage including an intermediate portion of a reduced diameter todefine an orifice, said nozzle body including a tapered passage having agradually reducing diameter from said mixing chamber to said orificediameter, said discharge passage having a substantially uniform diameterfrom said intermediate portion to the outlet end thereof to provide arelatively solid discharge stream.